In the earlier patent application SE 9400907-3, filed Mar. 18 1994, a method of encapsulating optocomponents by means of transfer moulding and of obtaining at the same time an optical interface in the wall of the capsule is described. This method is developed from the conventional encapsulating method for microelectronic circuits, where an electrically conducting leadframe is used for establishing an electric connection to microelectronic circuit chips. The leadframe usually consists of a punched or etched metal piece, e.g. of a thin copper or aluminium sheet. The leadframe comprises a special, suitably adapted portion termed "flag", onto which a microelectronic circuit is mounted before being moulded into the encapsulating material. Before the moulding embedment, the microcircuit chip is also electrically connected by friction welding, "bonding", by means of "bonding" wires to fingers and thereby also to legs of the leadframe.
Moreover, in encapsulation of optocomponents an optical interface is to be formed in the wall of the capsule having a high accuracy as to the position of the component in relation to another optocomponent or an optical connector device, to which the encapsulated component is to be connected. The required mechanical accuracy is achieved by mounting one or more optocomponents on a common carrier or substrate in the shape of a plate, which thereafter is attached to the flag. Finally the carrier is positioned in relation to the external geometry. For an optical interface, which is compatible with an optical multi-fiber contact of MT-device type, this is achieved by means of V-grooves on the carrier plate, in which guide pins extending through the mould cavity fit. These guide pins are pulled out after the encapsulation and then leave circular cylindrical holes in the encapsulation material. Into these holes, loose cylindrical guide pins are then inserted, at connection of the encapsulated optocomponent to a component having a similar interface.
The published European patent application EP-A1 0 452 634 discloses a leadframe intended for encapsulation of optical modules with a plastics material having several waveguides. In FIGS. 4-7 leadframes having flags intended for electronic circuit elements are shown, where portions of bridges between flag portions and a frame part extending at the edge are zigzag shaped in order to accommodate mechanical strains, which are caused by the plastics encapsulation. The zigzag shaped portions are located outside of the area the leadframe, which is contained inside the encapsulated module and which is shown by the dashed line P.
The published European patent application EP-A1 0 552 419 describes apparatus and a method for manufacturing optical modules by plastics encapsulation of amongst others optocomponents connected to a lead frame. In FIG. 6c it is shown how an optocomponent, using a wire W, is influenced by a pressing force for the purpose of obtaining an exact positioning.
Leadframes for semiconductor capsules are e.g. disclosed in U.S. Pat. No. 4,870,474 and 5,150,193 and in the published European patent application EP-A1 0 443 508. Optical components having leadframes are also discribed in U.S. Pat. No. 3,914,786 and the published European patent application EP-A2 0 446 410.